Concentration of ores



, frothing agents. The increased efficiency"- Patented Sept. 22, 1925.

UNITED STATES PAT N OFFICE.

CARL PIERCE LEWIS, 0F BURLINGAME, CALIFORNIA, ASSIGNOR MINERALS SEPARATION NORTH CORPORATION, QF NEW YORK, N. Y., A. CORPORA- TION OF CONCENTRATION OF OBIS.

N9 Drawing.

the presence of certain organic compounds containing sulphur.

It has been found that; certain sulphur derivatives of carbonic acid greatly increase -the efliciency of the froth-flotation process when used in connection with mineralshows itself. sometimes in markedl better recoveries, sometimes in effecting t e usual recoveries with greatly reduced quantities of the usual :mineral-frothin agents, and sometimes in greatly reducing the time needed for agitation to produce the desired recoveries.

' The invention is herein disclosed in some detail as carried out with salts of the sulphur derivatives of carbonic acid containing an organic radical, such as an alkyl radical, and known as xanthates as the new substance, These form anions and cations in solution. Excellent results were also ob tained by agitating ore pulpswith the complex mixture produced when 33 of pine oil was incorporated with an alcoholic solution of potassiumv hydrate, and xanthates or analogous-substances were-produced by adding carbon disulphide. to this. mixture.

The present application is in art a continuation of theapplication of ornelius H. Keller and myself, filed October 23, 1923,

Serial "Number 670,242, which has been changed: to a sole applicationof the said Cornelius H. Keller with claims for that" part of the invention described and claimed in said joint application whichwas in fact 7 the" sole invention ofthe said Cornelius H. Keller. The present a plication claims that part of the invention escribed and claimed- Application filed March 27, 1924. Serial No. 702,367.

be used in alkaline ore pulps or in ore pulps in which alkali has been=added, and this or other rocedure may be used to effect diiferentia l flotation of the various metal liferous minerals of complex ores. .TllO galena-bearing froth obtained with xanthates or analogous substances used at the rate of 0.2 pounds per ton of ore had a characteristic bright sheen, like a plumbago-bearing froth, and seemed to make a more coherent froth than when other materials were used on the same ore.

In eneral the substances referred to are not mineral-frothing agents, producing only a slight scum, and some evanescent frothy bubbles, when subjected to agitation which would produce mineral-bearing froth on an ore pulp in the presence of a mineral-frothing agent. The substances are effective in enabling a selective flotation of lead and zinc; and cause uncombined silver, if present, to tend to go into the lead concentrate rather than with the zinc, where these are separated in separate concentrates. Usual,- ly pre-agitation is unnecessary, the brightening and other effects seeming to be practically instantaneous.

For laboratory purposes potassium Xanthate .was prepared as follows:

198.4 grams of 88.5% caustic potash was dissolved in 524 grams ethyl alcohol (denatured #5 formula) at a temperature of 124 F.,-in a reflux condenser. The solution 'was cooled to 58 F. It contained'a large excess of alcohol over the theoretical amount needed for the subsequent reactions. To

this was added, while stirring, and in a cooling bath, the theoretical amount of carbon disulphide. The reaction was-substan tially instantaneous, producing a thick pulp of potassium xanthate. The pulp was cooled and centrifuged in a laboratory machine yielding crystals containing about.

20% moisture. The yield thus "obtained was 74.7%. Another 17.5% was obtained by evaporationof the-mother liquor. Both the centrifuged crystals and the residue from the mother liquor gave excellent results in flotationf It was found in cases where sulphuric acid was used that the centrifuged material yielded better results than the uncentrifuged.

A pulp of Cash Mine ore subjected first to agitation for-ten minutes with a mixture of 0.3 pounds per ton of potassium xanthate with a small proportion of a or a saturated solution of naphthalene in xylene, to yield a lead concentrate, and. then subjected to agitation for ten minutes with containing 87% of the silver but containing only 5% of zinc, while of the zinc was recovered in the zinc concentrate.

Cashv Mme ore, assays.

Au. Ag. is? (Oz) (0,) Cu. Pb. Zn. Fe. l

% RECOVERIES.

Au. Ag. Cu. Pb. Zn. Fe.

Pb cone.--" 59.4 87. 1 85. 2 95. 3 24. 7 68. 4 Zn cone 36.0 9.0 11.0 3.1 70.5 15.5 Tails.- 4. 6 3. 9 3. 8 1. 6 4. 8 16. 1

San Francisco Mines of Mexico.

Assays. Recoveries.

%Wt. 3% Pb. Zn. Ag. Pb. Zn.

-Heeds 100.0 10.5 0. 1 15.1 Pbcona. 12.2 01.0 04.0 12.0 40.4 83.2 9.1 Znconc- 28.9 23.0 3.0 43.4 41.2 11.1 78.0 58.9 4.5 1.5 0.0 0.4 5.7 12.0

Similar results were obtained with this ore by agitating for five minutes with 0.15 pounds each of sodium Xanthate and Barrett No. 2 flotation oil per ton of ore, to yield a lead concentrate, and then agitatin for ten minutes with 0.3 pounds copper su phate, 1.3 pounds Barrett No. 1 flotation oil, and General Naval Stores No. 5 flotation oil 0.1 pounds, all per ton of ore,

yield a zinc concentrate.

- Anaconda ore slimes containing 3.28%

copper of which 0.45% was acid soluble,

were subjected to froth-flotation concentration at 70 F. with 7.8 pounds per ton of in a sub-aeration machine at 17 C. with 2 pounds of soda ash, 0.7 pounds or" potasdry hydrated lime, 0.132 pounds per ton of steam distilled pine oil 0.38 pounds per ton of destructively distilled pine oil (G. N. S. #11 flotation), and 0.69 pounds per ton of potassium xanthate in solution, yielding concentrates containing 13.7 6% copper and 34.7% insolubles, with a tailing of 0.317 copper of which 0.173% was acid soluble. This represented a recovery of 92.2%.

The lime was mixed with water and fed as a watery paste with the slimes to the first agitator of a series of nine standard minerals separation agitators or mixing compartments through which the pulp passed in series at the rate of .97 tons in 24'hours. The #11 pine oil was added at the seventh agitator and 0.6 pounds per ton of the Xanthate at the ninth. The pulp returned through fourteen spitzkastens each equipped with a Brown aerator and circulating device. At the sixth spitzkasten the balance of the xanthate was added. At the tenth spitzkasten the steam distilled pine oil was added. The froth from the first nine spitzkastens was collected as a finished concentrate, that from the remaining five was returned to the first as a middling.

It has also been found that for the frotln flotation concentration of certain ores, such as Calumet & Hecla, Britannia, Cananea and Moctezuma, mother liquor obtained from centrifuging the above described Xanthates in the process of manufacture of said Xanthates may be used with about the same proportions of mother liquor as of the Xanthate crystals specified with results as good or better than those above given.

- In one test a freely flowing pulp containing 1200 grams of Anaconda slimes assaying 2.95% copper was agitated 15 minutes sium xanthate, and 0.2 pounds of steam distilled pine oil, all per ton of ore, yielding a concentrate containing 13.68% copper. The ratio of concentration was 5.2. The concentrate contained 91.5% of the copper, and an additional 4.1% was contained in a middling which held 0.68% of copper. The tailings contained 0.20% of copper which was 4.4% of that present in the heads.

The xanthate may be used to replace a part of the alkali normally used in the concentration of certain ores, and in differential flotation it may be used to replace either a part or all of the alkali normally used.

A pulp of Park Utah lead-zinc ore was agitated for ten minutes with potassium Xanthate 0.15 pounds, and Barrett #2 flotation oil 0.15 pounds, to yield a lead concentrate. The remainder of the pulp was then agitated fifteen minutes with soda ash, 1.5 pounds, copper sulphate, 0.5 pounds,

' to yield a lead concentrate. The remaining pulp was then agitated fifteen minutes.

water gas tar, 1 pound, and pine oil, 0.05 pounds, to yield a zinc concentrate. The zinc concentrate was then reagitated with added water for five minutes to yield a finished zinc concentrate and a zinc middling. All flotation and frothing agents were measured in pounds per ton. The results are shown in the following table:

A pulp of 80 mesh Calumet and Hecla slimes containing 0.44% copper, mostly native, with considerable mineral, occluded in the coarser particles .of the gangue, was agitated for twenty-five minutes with caustic soda 1 pound, potassium xanthate 0.25

pounds, N. T. U. oil 0.25pounds, and 0.25.

pounds pine oil and rosin mixed, all in pounds per ton. The results are shown in y Rwoveriesthe following table:

%w5. 35 Pb :21: Ag. Pb.. Zn. 7Recov- Assays o eries.

11.7 31.3 00.0 10.4 68.0 05.2 9.7 Cu Cm 20.3 42 1.7- 32.0 22.0 3.1 75.3

3.0 3.0 3.5 12.4 2.0 1.3 4.0 50.0 0.7 1.1 2.3 7.2 7.4 10.4 Heads mo I 1.0 12.24 440 21.4 0.88 43.2 Apulp of Sullivan ore was ag1tated for 0.068 12.0

seven minutes withpotassium xanthate 0.1-

pounds, and coal tar cre0sote,'0.1 pounds,

tion of water to produce respectively'a lead finished concentrate and middling and a zinc finished concentrate and middling. The results are shown'in the following table:

% Recoveries.

%Assays.

%wt 35- Pb. Zn. F0.- Pb. Zn. 111.

.A pulp of, the highly refractory ore of the North Star Mine of the Federal Mining 85 Smelting Co. was agitated for ten 'minutes with an added mixture of 90% potassium xanthate and 10% Barrett No. 2 creosote, 0.2 pounds, and with 0.1 pounds ofseparately added Barrett No. 2 creosote, to yield a lead concentrate. The remaining pulp was reagitated for fifteen minutes .with copper sulphate, 0.7 pounds, soda ash, 1.5 pounds, Barrett No. 4' flotation oil, 1.4 pounds, to yield a zinc concentrate. All weights are per ton of ore. The results 0 shown in the following table:

nolphthalein as indicator. Pulp thus treated when subjected to agitation with 0.1 to 0.15 pounds of a xanthate per ton and a minimum of mineral-frothing agents selects copper over iron more effectively than has hitherto been possible.

Phelps-Dodge table concentrates were ground with 5 pounds of lime per ton to make about 300-mesh material and then agitated in a pulp for five minutes with potassium xant ate, 0.10 pounds per ton, and steam distilled pine oil, 0.05 pounds per ton. to yield a concentrate. The pulp was then further agitated for fifteen minutes with an addition of potassium xanthate, 0.05 pounds per ton, and the'same pine oil, 0.05

pounds per ton, toyield a middling. The results areshown in the following table:

* Assays coveries.

'% Wt; Cu. F6. Cu.

Heads 100. 0 3. 71 Cone 1 8. 5 26. 88 31. 4 61. 7 Mldd 9. 4 8. 68 40. 7 22. 0 All! 82. 1 74 43. 3 16. 3

It will be noted that there was effective concentration of the copper, butno concentration of the iron e-ven'in this highly. re-

' fractory ore.

Having thus described certain embodiments of this invention what is claimed is:

i. The improvement in the concentration of minerals by flotation which comprises subjecting the mineral in the form of an alkaline pulp to a flotation operation in the presence of a xanthate.

'2. The improvement in the concentration of minerals'by flotation which comprises subjecting the mineral in the form of a pulp made alkaline by the addition of lime to a flotation operation in the presence of a Xanthate.

3. The improvement in the concentration of minerals by flotation which comprises subjecting the mineral in the form of an alkaline pulp to a flotation operation in the presence of potassium Xanthate.

a. The improvement in the concentration of minerals by flotation which comprises subjecting the mineral in the form of a pulp made alkaline by the addition of lime to a flotation operation in the presence of potassium Xanthate.

5. The improvement in the concentration of minerals byfiotation which comprises subjecting the mineral in the form of an alkaline pulp to a flotation-operation in the presence of potassium Xanthate and a frothing agent.

6. The process of concentrating an ore which consists in agitating a pulp of the ore with a sulphur derivative. of carbonic acid adapted to yield anions and cations in solution and with a mineral-frothing agent and an added alkaline substance to form a mineral-bearing froth and separating the froth.

7. The process of concentrating an ore which consists in agitating an alkaline pulp of the ore with a sulphur derivative of carbonic acid adapted to yield anions and cations in solution and with a mineralfrothing agent to form a mineral-bearing froth and separatin the froth.

8. The process 9'' concentrating a complex ore which consists in agitating a pulp of the ore with a sulphur derivative of carbonic acid adapted to yield anions and cations .in solution and with a mineralfrothing agent to form a mineral-bearing froth relatively rich in one mineral; separating the froth, further agitating the pulp with further added flotation agent to form a mineral-bearing froth relatively rich in another mineral, and separating the second froth.

9. ,The process of concentrating a complex ore which consists in agitating a pulp of the ore with a sul hur derivative of carbonic acid adapte to yield anions and cations in solution and with a. mineralfrothing agent to form a mineral-bearing froth relatively rich in one mineral, separating the froth, further agitating the pulp ass-seas -with the addition of flotation agent-includ ing an alkaline substance to form a mineralbearing froth relatively rich in :another mineral, and separating the second froth.

10. The process of concentrating an ore which consists in agitating a\ pulp of the ore with a xanthate and a mineral-frothing agent and an added alkaline substance to form a mineral-bearing froth and separating the froth.

11. lihe process of concentrating a complex ore which consists in agitating a pulp of the ore with a Xanthate and a mineralfrothing agent to form a mineral-bearing froth relatively rich in one mineral, separating that froth, and further agitating the pulp with further added mineral-frothing agent to form a second mineral-bearing froth relatively rich in another mineral, and separating the second froth.

12. The process of concentrating a compleX ore which consists in agitating a pulp of the ore with a Xanthate and a mineralfrothing agent to form a mineral-bearing froth relatively rich in one mineral, separating that froth, further agitating the pulp with an alkaline substance to form a second mineral-bearing froth relatively rich in another mineral and separating the second froth.

13. The process of concentrating a complex ore which consists in agitating a pulp of the ore with a xanthate and a mineralfrothing agent to form a mineral-bearing froth relatively rich in one mineral, separating that froth, further agitating the pulp with added flotation agent including an alkali to form a second mineral-bearing froth relatively rich in another mineral, and separating the second froth.

14. The process of concentrating a leadzinc ore which consists in agitating a pulp of the ore with a Xanthate and a mineralfrothing agent to form a lead-bearing froth, separating the froth, further agitating the pulp with further added mineral-frothing agent to form a zinc-bearing froth, and separating the second froth.

15. The rocess of concentrating an ore which consists in agitating a pulp of the ore with a sulphur derivative of carbonic acid containing an organic radical and with a 'mineral-frothing agent and an added alkaline substance to form a mineral-bearing froth, and separating the froth.

16. The process of concentrating an ore which consists in agitating an alkaline pulp of the ore with a sulphur derivative of carbonic acid containing an organic radical and with a mineral-frothing agent'to form a minerahbearing froth, and separating the froth.

In testimony whereof, I have affixed my signature to this specification.

CARL PIERCE LEWIS. 

